2095570637 - containing 5 mL of ice water. Rinse the vial...

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Reduction of Camphor There are many reagents that are useful for the reduction of various carbonyl compounds. Reagents such as sodium borohydride and lithium aluminum hydride act as hydride sources, which undergo nucleophilic addition reactions with aldehydes and ketones to yield alcohols. In this experiment, you will reduce camphor, a naturally occurring ketone, using sodium borohydride. The reduction produces a mixture of alcohol stereoisomers, isoborneol and borneol, in a 6:1 ratio. O C H 3 CH 3 C H 3 C H 3 CH 3 C H 3 H OH C H 3 CH 3 C H 3 OH H 6:1 Isoborneol Borneol 1) NaBH 4 2) H 2 O Safety: Methanol is toxic to the optic nerve. Procedure: In a 5 mL vial, dissolve 200 mg of camphor in 2 mL methanol. Obtain 100 mg of NaBH 4 , and add this in four portions to the camphor solution over the course of five minutes, swirling after each addition. Attach a condenser and gently reflux the mixture for 5 minutes. Let the mixture cool to room temperature and then pour it into a small beaker
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Unformatted text preview: containing 5 mL of ice water. Rinse the vial with an additional 2 mL of water to aid the transfer. Collect the crude product by vacuum filtration. Allow the vacuum to pull for about 10 minutes to dry the solid. Recrystallize the solid from petroleum ether and collect the purified solid by vacuum filtration. Determine the weight of the dry solid and obtain an IR spectrum for your isoborneol. Write Up: Calculate the percent yield (show the calculation) and interpret the IR spectrum of your product. Make note of the presence and absence of any significant absorptions and what they indicate. Questions: 1. Why is the major product of this reduction isoborneol and not borneol? 2. The reduction in this experiment gives largely isoborneol to the exclusion of borneol. Starting from camphor, provide a multi-step synthesis that would favor borneol over isoborneol....
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